Hubble Space Telescope

Hubble Space Telescope

The Hubble Space Telescope is perhaps the most famous and successful space observatory. It is named after the astronomer Edwin Hubble. The HST was launched into orbit around Earth by NASA in 1990 in a space shuttle. It orbits at a height of about 560 km above Earth and completes a period in about 96 minutes. The HST is about 13.3 m long and its primary mirror is 2.4 m in diameter. It is powered by two large solar panels. They are able to keep it working through servicing missions and equipment upgrade every few years. Since 1993, NASA has sent 5 servicing missions.

The HST is a type of telescope knows as a Cassegrain reflector. The light hits the primary mirror and bounces of to a secondary, smaller mirror. The secondary mirror then focuses the light into a small aperture in the center of the primary mirror that leads to the telescope's instruments and measuring devices. The HST does not have one of the biggest mirrors telescope, but what makes it successful is its location. The atmosphere above Earth distorts and blocks some of the light that comes from space. The HST orbits high above Earth to avoid this problem.  

The HST has 6 major instruments:

• The Wide Field Camera 3, Which can measure light at 3 different wavelengths: near-ultraviolet, visible, and near-infrared. This instrument will be used to study dark matter and dark energy, the formation of individual stars, and the discovery of galaxies that are extremely far.
• The Cosmic Origins Spectrograph, which can only see in ultraviolet light. The spectrograph will separate the light into its components.
• The Advanced Camera for Surveys, which can see visible light. It studies the early activity in the universe. 
• The Space Telescope Imaging Spectrograph, which can see ultraviolet, visible, and near-infrared light. The STIS is know for its ability to locate black holes.
• The Near Infrared Camera and Multi-Object Spectrometer, which can detect heat, or infrared light. It is useful for finding object in interstellar dust  
• The Fine Guidance Sensors, which are targeting cameras that measure and track the movement of an object.

The HST pictures have helped scientists estimate the age and size of the universe. The HST has also helped scientists understand the formation of galaxies and planets A picture called "Hubble Ultra Deep Field" shows the farthest galaxies ever seen. The HST has also spotted black holes and has helped in the discovery of dark energy. It has also helped scientists learn more about the death of supernovas and giant stars.

Scientists at NASA hope to keep the Hubble Space Telescope operational for another 5 years.

Sources:

http://hubblesite.org/the_telescope/hubble_essentials/#work

http://www.nasa.gov/mission_pages/hubble/story/index.html#.UvsGsHdQ-uO

http://en.wikipedia.org/wiki/Hubble_Space_Telescope#Major_projects